The leukotrienes constitute a group of locally acting hormones, produced in living systems from arachidonic acid. The major leukotrienes are Leukotriene B.sub.4 (abbreviated at LTD.sub.4), LTC.sub.4, LTD.sub.4 and LTE.sub.4. The biosynthesis of these leukotrienes begins with the action of the enzyme 5-lipoxygenase on arachidonic acid to produce the epoxide known as Leukotriene A.sub.4 (LTA.sub.4), which is converted to the other leukotrienes by subsequent enzymatic steps. Further details of the biosynthesis as well as the metabolism of the leukotrienes are to be found in the book Leukotrienes and Lipoxygenases, ed. J. Rokach, Elsevier, Amsterdam (1989). The actions of the leukotrienes in living systems and their contribution to various diseases states are also discussed in the book by Rokach.
U.S. Pat. No. 4,957,932, Young et al. discloses compounds similar to those of formula 1 as leukotriene antagonists and inhibitors of leukotriene biosynthesis. The present compounds differ from Young's primarily in having a different heterocyclic ring on the left side of the structure. Fujikawa describes the thieno[2,3-b]-pyridine 2 in EP 367,235 but the point of attachment and the nature of the principal substituent are different from the present compounds. Musser et al. describe compound 3 in U.S. Pat. No. 4,794,188 as being lipoxygenase inhibitors and possessing anti-inflammatory and anti-allergic activities. However, compound 3 differs from the present compounds principally in that Ar.sub.1 is different from our HETA grouping. Thus, the compounds of the present invention are novel. ##STR2##
Young, et al. U.S. Pat No. 4,957,932 ##STR3##
Fujikawa EP 367,235 EQU Ar.sub.1 --X--Ar--Z--(R).sub.n' 3.
Musser et al. U.S. Pat. No. 4,794,188.